Transitioning between system sharing types in multi-tenancy database systems

The present disclosure teaches solutions for transitioning between database system sharing types. In one example, a tenant container includes a read-only table, a first writable table, and a mixed table for storing read-only and writable data. When transitioning to a sharing setup, a shared container is created and a shared table is created in the shared container. Data is copied from the read-only table to the shared table and the read-only table is dropped. A read-only view is created in the tenant container and a second shared table is created in the shared container. Read-only mixed data is copied from the mixed table to the second shared table and deleted from the mixed table, and after the deletion, the mixed table is renamed as the second writable table. A union view is created that provides unified access to the second shared table and the second writable table.